Scheduled workflow not running on a fork in CI

When you fork a repository, GitHub does not run its scheduled workflows in your fork. Actions are often disabled on new forks, and even when enabled, schedules only run in the fork if you enable Actions and the workflow file is on the fork default branch.

What this error means

You forked a repo that has a nightly cron, and no scheduled runs ever appear in your fork. Push-triggered runs may also be off until you enable Actions.

GitHub Actions UI (fork)

Workflows aren't being run on this forked repository.
Because this repository contained workflow files when it was forked,
we have disabled them from running on this fork.

Common causes

Actions are disabled on the fork

GitHub disables workflows on new forks by default, which includes all scheduled triggers.

The schedule file is not active on the fork default branch

Even after enabling Actions, the cron only runs if the workflow lives on the fork default branch.

How to fix it

Enable Actions in the fork

Open the fork Actions tab and confirm you want to enable workflows.
Ensure the scheduled workflow file is on the fork default branch.
Wait for the next cron slot or trigger manually to confirm it runs.

GitHub Actions UI

# In the fork: Actions tab > "I understand my workflows,
# go ahead and enable them"

Prefer workflow_dispatch for fork verification

Add workflow_dispatch so contributors on a fork can run the workflow manually without waiting for a schedule that may not be enabled.

.github/workflows/nightly.yml

on:
  schedule:
    - cron: '0 3 * * *'
  workflow_dispatch: {}

How to prevent it

Enable Actions explicitly after forking if you need the cron.
Document that schedules must be re-enabled in forks.
Provide workflow_dispatch as a fork-friendly manual entry point.